Conventionally, in order to provide for infusion into a patient, a plurality of tubes are interconnected to structure an infusion line for fluid flow from an infusion bag to a patient. The plurality of tubes are interconnected through a connector. Upon infusion, a main infusion solution may be infused into a patient through a main line, and another line may be provided to supply another infusion solution therethrough. The other infusion solution may be mixed with the main infusion solution at the connector and guided to the patient. In this case, the connector includes three ports through which the infusion solutions flow, and can also include a three-way stopcock or the like that can arbitrarily switch the flowing state of infusion solutions, such as in the connector disclosed in JP 3719443 B1.
The connector disclosed in JP 3719443 B1 includes first and second ports constituting a main line passage and a third port constituting a second line passage in its body. A cock (a switching part) configured to switch communication between the first to third ports is also provided in the body. Since a male connector of a second line has to be inserted into and connected to the third port, the third port defines a space connected to the main line passage in between the passages of the first and second ports and formed to have a larger diameter than the main line passage and a relatively large volume.
In a state where the male connector of the second line is not connected (i.e., the third port is closed), a phenomenon can occur in which fluid of the infusion solution or an air pocket stagnates in the space. Fluid stagnating in such a space (hereinafter also referred to as stagnating fluid) may lead to various unfavorable effects.
For example, when an infusion line is filled with an infusion solution to evacuate air before infusing an infusion solution into a patient, air bubbles may stagnate in the space. The remaining air bubbles may be unfortunately delivered to the patient together with the infusion solution upon infusion of the infusion solution into the patient. In addition, when highly nutritious liquid is supplied as an infusion solution, stagnation of this liquid in the space may increase germs in the connector, and the germs may be unfortunately delivered to a patient. Further, upon switching of infusion solutions to be supplied to a patient, a previous infusion solution may be left in the space when a next infusion solution is supplied, and thus different infusion solutions may be undesirably mixed and delivered to a patient.
In order to reduce the possibility of these and other unfavorable effects resulting from stagnating fluid in the space, a connector can be structured to divert infusion solution flowing through the inner passage and guide the infusion solution to the space. The infusion solution guided to the space forces stagnating fluid to flow, and thus facilitates discharge of the stagnating fluid from the space.
Meanwhile, the connector disclosed in JP 3719443 B1 has a space larger than the inner passage, and thus a step part is formed on the boundary between the inner passage and the space. In such a connector, infusion solution doesn't flow toward the step part of the space even when the infusion solution is guided to the space, and so the connector can have a problem in that stagnating fluid still remains at the step part. In particular, a connector applied in an infusion line may be used in various orientations and the third port may point up or may be sideways, for example. Therefore, depending on the orientation of the connector in use, a relatively large amount of stagnating fluid may stagnate at the step part of the space, and the unfavorable outcomes caused by stagnating fluid as described above are not sufficiently reduced.